OBJECTIVE: Quantitative analysis of DNA in human metaphase chromosomes. METHODOLOGY: Quantitative cytochemistry, digital scanning cytophotometry, real-time interactive image processing and analysis by computer, biostatistical evaluation of results. These technologies are combined into a system of unique power and sensitivity that can detect and measure effects involving as little as 6x10 to the negative 15g power of DNA. APPLICATIONS: Use chromosomal measurements of relative DNA stain content and of DNA-based centromeric index to: a) Establish the mean and variation of the 'normal' human karyotype. b) Estimate the incidence of DNA-variant chromosomes within the population. c) Use familial studies to investigate the heritability of DNA variant chromosomes. d) Apply this approach to a variety of clinical problems, including analysis of the specific translocation of chronic myelogenous leukemia. BIBLIOGRAPHIC REFERENCES: J.W. Gray, A.V. Carrano, L.L. Steinmetz, M.A. Van Dilla, D.H. Moore II, B.H. Mayall, and M.L. Mendelsohn, "Chromosome Measurement and Sorting by Flow Systems", Proc. National Acad. of Sci., U.S.A., Vol. 72, No. 4, pp. 1231-1234, 1975. J.W. Gray, A.V. Carrano, D.H. Moore II, L.L. Steinmetz, J. Minkler, B.H. Mayall, M.L. Mendelsohn and M.A. Van Dilla, "High-Speed Quantitative Karyotyping by Flow Microfluorometry", J. Clin. Chem. 21/9, 1258-1262, 1975.